Gas turbine fuel nozzles typically comprise an outer air swirler which is, in use, exposed to higher temperatures than the rest of the fuel nozzle, and is therefore subject to thermal stressing which can cause cracking particularly when the air swirler is a two-piece construction comprising a cap rigidly secured on an air swirler vane body. The thermal differential growth between the cap and the swirler vane body results in high stresses in the swirler vane as well as in the joints between the cap and the body. These thermally induced stresses negatively affect the Low Cycle Fatigue (LCF) life of the fuel nozzle.
While there is a need to improve the durability of fuel nozzle air swirlers, the proposed solutions should have as little impact as possible on the aerodynamic performances of the air swirler.